Talking-machine record



, so-called tal Patented May 17, 1927.

UNITED STATES PATENT OFFICE.

v FRANK L. DYER, 0F MONTCLAIR, NEW JERSEY.

TALKING-MACHINE RECORD.

Original application filed May 7, 1923, Serial No. 637,198. Divided andthis application filed February 12, 1924. Serial No. 692,293.

This application is a division of application filed May 7, 1923, SerialNo. 637,198. In said application I describe and claim certainimprovements in the art of recording and reproducing sounds, in whichthe improved talking machine record herein described and. claimed isutilized.

As now made, talking machine records permit the recording of sounds overa very limited period of time, generally in the neighborhood of threeminutes, more or less; as a result any music recorded thereon isnecessaril abridged and mutilated, and

li ing records are limited in subject matter.-

The limitation as to time in existing talking machine records is madenecessary by the conditions of the art as now practiced. It being anessential that the sounds which are'to be directly reproduced from therecord shall be loud enough to fill a large sized room, it has beenfound necessary to make" ponderous sound-box use of a relatively carring a relative y large diaphragm, the who e resting upon a pointedneedle which tracks the record and which engages the record with apressure of many thousand pounds per square inch. To prevent such aneedle from cutting and destroying the record material with which itengages, it is necessary that the record material should be moved withrespect to the needle at a relatively high speed, and experience hasshown that a mean surface speed in the neighborhood of 40 inches persecond is desirable in, practice. It has been found that at this surfacespeed of the material a sound-box of sufficient weight to give thenecessary sounds can be supported by a needle with commercial results asto wear, provided the record groove is of sutlicient width to give arelatively extended bearing surface for the needle when the point of thelatter has worn down sufliciently to fill a substantial portion of therecord groove, and therefore it is the present practice to make theserecord grooves substantially .005 inch in width and with a depth rangingfrom .002

to .003 inch.

The amplitude of the sounds reproduced from the record depends upon theextent to which the groove may vary on either side of its medial line orin other words upon the amplitude of the lateral or vertical undulationsof the record groove, and I have of .005 inch, corresponding with thatof the record groove. These limitations as to width of groove, width oflands, and surface speed make 1t 1mposs1ble with a record disk of adiameter of 10 or 12 inches or thereabouts, or a corresponding cylinder,to secure a sound record of much more than 3 minutes in length, withcorresponding restriction as to character and subject matter.

What I propose by my present improvements, is to very greatly extend thecapacity of a record of the present standard size by obtaining thereon arecord of sounds of an hour or more representing an extension of 25 foldas to time. In this way it will become possible to record very longmusical compositions or to record several long musical compositions onone face of a record; it will become possible to make a record ofstories of considerable length; it will become possible on two or threedouble faced records to record an'entire novel, since three recordswould represent six hours of solid reading; and it will become possibleto record upon a record disk of very small size'a much longer selectionthan can possiblybe recorded and satisfactorily reproduced underexistino' conditions on records of standard size. y improved record willbe especially acceptable to the blind, to whom reading by existingmethods is tedious and unsatisfactory.

What I propose, in brief, is to make a record groove of microscopicsize, prefers ably of the order of .001 inch in width, or at leastsubstantially and materially narrower than any talking machine record ofwhich I have knowledge. The depth of the groove frequently cut recordgrooves of the order of a thousandth of an inch in width and The soundswhich I record in such a groove of extreme narrowness and formed at lowspeed are so controlled or adjusted that the recorded amplitude thereofwill .bear substantially the same ratio to the surface speed as withexisting practice; that is to say, if the maximum amplitude of sounds asrecorded on present records is of the order of .001 inch, then with myimproved record the recorded amplitude will be approximately .0002 inch.This control of .the

1 sounds to be recorded may be, effected in many ways, as by usingoriginal sounds of small volume, or by using a recording diaphragm ofrelatively great thickness to limit the amplitude of its response, or byusing a recording diaphragm of small diameter so as to have a limitedresponse, or by adjusting the leverage of the needle arm of therecording device whereby the movement of the cutting stylus will beproperly limited.

It will be seen that the proposed record will have substantially thesame relations as to width, surface speed and amplitude as existingrecords. With such a record it becomes possible to make a proportionatere duction in the pitch of the record groove; with the example underconsideration the pitch will be reduced from .01 inch to .002 inch.

Bycutting down the pitch of groove fivefold and by reducing the surfanspeed fivefold, I increase the time represented by the record groovetwenty-five fold or, say, from three minutes to seventy-five minutes,while at the same time the record groove has sounds recorded thereon inproper relation to the surface speed as well as to the width of grooveand width of lands between the grooves. The sounds recorded in thegroove differ only from the sounds in the grooves of existing records inthe respect that they are of less amplitude, but otherwise they areperfectly and accurately formed. Being recorded at low speed andinvolving the removaLof a minute amount of material the recorded soundsare relatively free of distortions noticed in existing records which..are due to removal of relatively large amounts of material atmelative'ly high speeds.

Such a record as I have above proposed,

could not be used effectively for direct reproduction; a sound boxfor/that purpose would have to be too heavy and direct reproductionunder any circumstance would be weak, owing tothe limited amplitude ofthe recorded sounds. I, therefore, propose to use a reproducing devicebearing upon the record with a pressure proportional to the width andlength of the groove, say with a pressure of from one-quarter toone-half an ounce, and by suitable amplifying means I increase thevolume of the sounds to the desired extent. It is possible to useexterior amplifying means to enlarge the comparatively feeble sounds onthe record to any desired extent; to as loud or louder thanexisting-records with direct reproduction, while at the same time thewear on the improved record is no greater than with present records. Thesounds from my improved record maybe amplified in any suitable way, forinstance, for reading, ordinary listening tubes or a simple telephonemay be employed, while if loud effects are wanted, the feeble sounds onthe record may be amplified by an ordinary loud-speaker of the radiotype or some such device having as many stages of amplification as maybe desired. Devices of this kind are capable of producing enormousamplification with but relatively little distortion. tubes or astethoscope is used as an amplifying device, it will be understood thatthe reproducing device will be equipped with a small light diaphragm,actuated directly from the record, but i the amplifying device iselectrical, as is preferred, then the needle tracking the recordgroovewill actu- If listening i ate a suitable microphone, the varyingcurrents of which will either actuate a telephone receiver directly orbe amplified before reception by any suitable arrangement of thermionicvalves or other amplifiers.

In order that the invention may be better understood, atention isdirected to the ac companying drawings forming part of. thisspecification, and in which:

Fig. 1, is a cross sectional view of a record of the ordinary type anddimensions, illustrating three of the grooves, with the lower end of aneedle engaging thecenter groove;

vFig. 2, a corresponding cross section through my improved record, onthe same scale, with a needle engaging one of the grooves;

Fig. 3, a plan view of the standard record shown in Fig. 1; and

Fig. 4, a similar view of the improved record. v y

In all of the above views corresponding parts are represented by thesame reference characters.

Referring first to Figs. 1 and 3, 1 repre-' sentsa small portion of anordinary record having a'record groove 2 therein; ordinarily this recordgroove is about .005 inch in width, about .002 in depth, and with apitch of .01 inch or one hundred threads to the inch. In Fig. 3, thegroove is shown as having a deflection, representing sound, of .001inch, this being the order of amplitude of maximum sounds recorded ontalking machine records. It will be understood that the record is aduplicate copy obtained in the usual way from a suitable master cut inan amorphous and uniform material in the usual way.

Referring now to Figs. 2 and 4. the record roove 3, shown therein isillustrated as belng one-fifth the width of-the ordinary groove andone-fifth the relative length thereof; that 'is to 'sa the groove is.001 inch in width and tile surface speed at which it is formed isapproximately eight inches per second, average; its depth issubstantially proportional to the standard record shown in Figs. 1 and3. With these proportions the record, as shown in Fig. 4 has onetwenty-fifth the area of the standard record and hence the time ofreproduction is increased twenty-five fold.

It is of course not necessary that these dimensions shall be preciselyfollowed; by reducing the width of the groove and proportionatelyreducing the surface speed the time of reproduction is increased inproportion to the product ofthe two factors; a record of one-third theusual width and one-third the speed will represent a nine-fold increasein time, and so on. It is important that there should be a substantialreduction in the width and surface speed as compared with presentpractice, since the opportunity of exterior amplification is practicallyunlimited and the important consideration is to increase the time ofreproduction at least several fold so as to thereby extend the talkingma chine into fields that are now unthought of,

It will be observed that the amplitude of the recorded sound in Fig.4 isproportional to that of Fig. 2, so far as width and length areconcerned. In other words, the maximum amplitude with a record groove of.001 inch should be of the order of .0002' inch. As I have indicated asound groove of this sort can be obtained in various ways, but of theexpedients suggested. I prefer to secure the desired limited range ofamplitude by using an ordinary recording apparatus operated in the usualway, but I so adjust the leverage of the arm or lever which carries thecuttin tool that the deviation of the cutting too will be properlyreduced in extent; in the assumed case, the levera e will be such. thatthe cutting tool will vibrated only one-fifth as far on either side ofthe medial line as with. present pr actice.

As indicated, the feed. or pitch of the N ord groove is reduced inproportion to the width, that is to say when the width of the groove isreduced to .001 inch, the pitch of the groove will be reduced to .002inch or live hundred threads to the inch.

The needle 4 which tracks the groove of my improved record is properlyproportioned to the size of the groove and has practically the samerelation thereto as the ordinary needle 5 tracking the regular sizedgroove 2; in use the relatively pointed end will quickly wear down toincrease the bearing surface and fill the groove more or less; it isimportant that the extremity of the .needle shall have the rightproportion; the

shank may be relatively large so as to give v rigidity and permit theneedle to be handled more easily. I find, that the ordinary re-' cordingmaterial is so uniform and amorphone that a sound gro ove of .001 inchin width may be cut therein with beautiful sharpness and clearness;moreover the methods now used of making duplicate .copies from masterrecords are so very perfeet that even when the record has been reducedin width five fold as contemplated herein the copies obtained from sucha master will be practically perfect and free from foreign sounds.

In securing reproduction from such a record as I have above described, Itake advantage of exterior amplifying devices and I prefer to have therecord actuate a microphone rather than a diaphragm as when theamplification is secured by the use of a stethoscope.

In my said application filed May 7 1923, Serial No. 637,198, of whichthis is a division, I describe as an embodiment of the inventionelectrical appliances by which amplification is secured, and it istherefore not necessary to illustrate the same herein since the presentapplication relates to my improved talking machine record per se.

While I have specifically described my improved talking machine recordas having a groove of the laterally un-dulatory type, it will beunderstood that the invention may be carried out with records havinghill and dale grooves, it being only necessary to properly proportionthe width, length and amplitude'as herein described. If the hill anddale grooveis adopted, I prefer to form the same with the wedge shapecutter, giving substantially the cross-section of Fig. 3. With such agroove, a needle may be used for reproduction, and will track the amond,and di culty it reduced to the microscopic dimensions 1 contemplated'hymy invention.

Having now described my invention,

what I claim as new therein and desire to secure by Letters Patent, is:

v 1. An improved talking machine record having a sound groove materiallyless than .005 inch in width, and representing sounds recorded at asurface speed materially 'less than forty inchesper second.

2. An improvedtalking machine record having a sound groove materiallyless than inch.

4. An lmproved talklng machine record having a record groove materiallyless than .005 inch inwidth and representing sounds recorded at. asurface speed materially less than forty inches per second, said groovebeing in theform of a spiral, the pitch of which is materially less than.01 inch and the recorded sounds being of a maximum amplitude materiallyless than .001 inch.

v5. An improved talking machine record having a sound grooveapproximately .001 inch in width and representing soundsrecorded at asurface speed of approximately eight" inches per second.

, 6. An improved talking machine record having a sound grooveapproximately .001

inch in width and representing sounds recorded at a surface speed ofapproximately eight inches per second, said groove being in the form ofa spiral the-pitch of which is approximately .002 inch.

7. An improved talking machine record having a sound grooveapproximately .001 inch in Width and representing sounds recorded at asurface speed of approximately eight inches per second, and or a maximumamplitude of approximately .0002 inch.

8. An improved talking machine record having a sound grooveapproximately .001 inch in width and representing sounds recorded at asurface speed of approximately eight inches per second, said groovebeing in the form of a spiral the pitch of which is approximately .002inch and the recorded sounds being of a maximum amplitude ofapproximately .0002 inch.

9. An improved talking machine record, comprising a record disk ofstandard 'size, a sound groove therein materially less than .005 inch inwidth and representing sounds recorded at a surface speed materiallyless than forty inches per second, said groove being in the form of aspiral, the pitch of which is materially less than .01 inch.

10. An improved'talking machine record, comprising a record disk ofstandard size,

a sound groove therein approximately .001

inch in width and representing sounds recorded at a surface speed ofapproximately eight inches per second, said groove being in the form ofa spiral the pitch of which is approximately .002 inch.

This specification signed this 11th day of February, 1924.

- FRANK L. DYER.

